On Fri, May 30, 2025 at 5:57 PM Melanie Plageman
<melanieplage...@gmail.com> wrote:
> I don't see how OldestXmin comes into play with the visibility_cutoff_xid.
Code in heap_page_is_all_visible() (and other place, I guess the other
one is in pruneheap.c now) have a separate OldestXmin test:
/*
* The inserter definitely committed. But is it old enough
* that everyone sees it as committed?
*/
xmin = HeapTupleHeaderGetXmin(tuple.t_data);
if (!TransactionIdPrecedes(xmin,
vacrel->cutoffs.OldestXmin))
{
all_visible = false;
*all_frozen = false;
break;
}
Once we "break" here, it doesn't matter what visibility_cutoff_xid has
been set to. It cannot be used for any purpose.
--
Peter Geoghegan
